OAuth callback not received by app after successful browser authentication — Windows 11

Google Antigravity
1

Environment

  • OS: Windows 11
  • Antigravity IDE version: Latest (downloaded from antigravity.google)
  • Browsers tested: Chrome, Edge
  • Account type: Personal Gmail
  • Network: Home Wi-Fi, no VPN, Windows Defender only

Problem
After clicking “Sign in with Google”, the browser opens and authentication completes successfully. The browser console logs:

Launched external handler for ‘antigravity-ide://oauth-success’

However, the Antigravity IDE never receives the callback and remains stuck on the login screen with no error message.

What I’ve already tried

  • Cleared cookies for google.com and antigravity.google
  • Tested with both Chrome and Edge
  • Added Antigravity IDE to Windows Firewall allowed apps
  • Verified registry entry at HKEY_CLASSES_ROOT\antigravity-ide — it exists and points to the correct path:
    “C:\Users\DELL\AppData\Local\Programs\Antigravity IDE\Antigravity IDE.exe” “–open-url” “–” “%1”
  • Ran the app via runas /trustlevel:0x20000 to force non-admin privileges
  • Manually triggered the protocol URL via PowerShell — no response from the app
  • Checked chrome://settings/handlers — no antigravity-ide entry present

Additional observation
When launching the app with administrator privileges via PowerShell, the login flow proceeds further but fails with: “Another instance of Antigravity IDE is already running as administrator.” — even when no other instance is open.

The protocol handler appears to be registered correctly in the registry, but the app never receives or processes the OAuth callback. Any help would be appreciated.

added:

Additional log errors found in ls-main.log: - state syncing error: key not found (repeated) - Failed to get OAuth token: error getting token source from auth provider: state syncing error: key not found - Auth succeeded, refreshing features and managers (auth succeeds but token cannot be stored) - failed to install playwright: got non 200 status code: 404

2

Hi @HanByul_Kim, Welcome to the Forum!

Could you please follow these steps:

  • Completely close Antigravity and end any remaining Antigravity-related processes from Task Manager.
  • Back up the following folder if it exists: %USERPROFILE%\.gemini\antigravity
  • Rename the folder to something like antigravity_backup rather than deleting it.
  • Restart Windows.
  • Launch Antigravity normally as a standard user (not as Administrator).
  • Start the Google sign-in flow again.
  • If the issue persists, please collect the latest ls-main.log immediately after the failed sign-in and share the relevant authentication/state-sync errors.
3

first, Thank you.

I followed all the steps you suggested, but the issue persists.

  • Renamed %USERPROFILE%.gemini\antigravity-ide to antigravity-ide_backup
  • Restarted Windows
  • Launched as standard user
  • Signed in again

The new ls-main.log shows the exact same errors as before.
(Note: URLs in the log below have been changed from https:// to hxxps:// due to new user posting policy.)

Key observation: “Auth succeeded” appears in the log, meaning authentication
itself works — but immediately after, every token read attempt fails with
“state syncing error: key not found”.

It seems the token is written somewhere the language server cannot access.
Please advise on what the correct token storage path should be on Windows.

[log]
2026-08-19 18:50:42.597 [error] [LS Main stderr] ERROR: logging before google.Init: I0819 18:50:42.596910 1 server.go:2697] Auth succeeded, refreshing features and managers
ERROR: logging before google.Init: E0819 18:50:42.597453 1 errorreport.go:223] Failed to poll ListExperiments: error getting token source: state syncing error: key not found

2026-08-19 18:50:43.310 [error] [LS Main stderr] ERROR: logging before google.Init: E0819 18:50:43.309457 101 browser_context.go:179] failed to install playwright: could not install driver: could not install driver: error: got non 200 status code: 404 (404 Not Found) from hxxps://playwright.azureedge.net/builds/driver/playwright-1.57.0-win32_x64.zip
error: got non 200 status code: 404 (404 Not Found) from hxxps://playwright-akamai.azureedge.net/builds/driver/playwright-1.57.0-win32_x64.zip
error: got non 200 status code: 404 (404 Not Found) from hxxps://playwright-verizon.azureedge.net/builds/driver/playwright-1.57.0-win32_x64.zip

2026-08-19 18:50:47.451 [error] [LS Main stderr] ERROR: logging before google.Init: E0819 18:50:47.448176 87 server.go:719] Failed to get OAuth token: error getting token source from auth provider: state syncing error: key not found